Stable and reliable starting control method, device and system for double permanent magnet motors of belt conveyor

Abstract

The invention discloses a stable and reliable starting method, device and system for double permanent magnet motors of a belt conveyor. According to the method, one permanent magnet motor is set as a master machine, and the other permanent magnet motor is set as a slave machine. In the open-loop starting stage, the starting electrical angular velocity of the slave is compensated and corrected by using the power difference between the master and slave machines, so that the output power of the two permanent magnet motors in the open-loop starting stage is approximately equal; in the closed-loop starting stage, the starting rotating speed of the slave is compensated and corrected by using the q-axis current difference of the master and slave machines, so that the output electromagnetic torques of the two permanent magnet motors in the closed-loop starting stage are approximately equal. An optimization strategy of switching from an open loop to a closed loop in the starting stage is designed, and the rotating speed impact in the switching stage is reduced. The method is beneficial to improving the starting capability of the belt conveyor, and has important significance on reliable and stable operation of the belt conveyor.

Description

Technical Field

[0001] The invention belongs to the field of motor control, and in particular relates to a method, a device and a system for stably and reliably starting a dual permanent magnet motor of a belt conveyor. Background Art

[0002] Permanent magnet motors have the characteristics of high efficiency, high power density and excellent control performance. They are used in mining belt conveyors and have outstanding advantages. They can not only save electricity but also improve the control performance of the speed control system. In the field of mining belt conveyors, in order to save costs and improve system reliability, permanent magnet motor control mostly adopts position sensorless control methods and adopts a distributed drive method of two permanent magnet motors. In order to overcome the static friction during the startup phase, the belt conveyor has a high demand for starting torque, which puts forward high requirements for the starting method of permanent magnet motors. The positionless starting scheme of permanent magnet motors mainly includes three methods: open-loop starting, high-frequency injection and model-based observer method. The high-frequency injection method needs to rely on the salient polarity of the motor. For permanent magnet motors with low salient polarity, its starting ability is greatly weakened. The model-based observer method relies on the accurate model of the motor. When the starting current is large, the magnetic circuit of the permanent magnet motor will inevitably have saturation and nonlinear problems, which will have a great impact on the control accuracy of the observer. The open-loop starting scheme means that a fixed starting current is given and the adaptiveness of the motor mechanical model is used to complete the starting. It does not rely on the saliency and mathematical model of the motor. Therefore, it has higher reliability and adaptability than the other two schemes. In actual sites, open-loop starting is often used to reach a certain speed and then enter the model-based observer closed-loop starting process.

[0003] However, when using dual permanent magnet motors for drive, the open-loop starting scheme cannot accurately obtain the motor speed information. When the roller diameters corresponding to the two permanent magnet motors are different, the two motors will have the same linear speed but different speeds, which can easily lead to power imbalance. One motor may even produce a reaction force and report an overvoltage shutdown, which seriously restricts the starting ability of the belt conveyor.

[0004] In addition, during the closed-loop startup phase, when the friction between the two rollers is inconsistent due to factors such as roller wear, roller moisture, and belt slippage, the output of the two motors will be uneven. In severe cases, one of the motors will overspeed, seriously affecting the smooth operation of the belt conveyor. Summary of the invention

[0005] The object of the present invention is to provide a method, device and system for smoothly and reliably starting and controlling a dual permanent magnet motor of a belt conveyor, so as to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] In a first aspect, the present invention provides a method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor, wherein one of the dual permanent magnet motors is set as a master motor and the other permanent magnet motor is set as a slave motor, and the method comprises:

[0008] In the open-loop startup phase, the power difference between the master and slave motors is used to compensate and correct the starting electrical angular velocity of the slave motor, so that the output powers of the two permanent magnet motors are approximately equal in the open-loop startup phase;

[0009] During the closed-loop startup phase, the difference in q-axis current between the master and slave motors is used to compensate and correct the starting speed of the slave motor, so that the output electromagnetic torques of the two permanent magnet motors are approximately equal during the closed-loop startup phase.

[0010] In one embodiment, during the open-loop startup phase, the power difference between the master and slave motors is used to compensate and correct the starting electrical angular velocity of the slave motor so that the output powers of the two permanent magnet motors are approximately equal during the open-loop startup phase, including:

[0011] The open loop start of the main motor gives a given electrical angular velocity Directly set to As the electrical angular velocity reference value of the main motor in the open-loop startup phase, The maximum value is about 10% of the rated electrical angular velocity of the permanent magnet motor;

[0012] In the two-phase stationary αβ coordinate system, calculate the active power P1 and P2 of the master motor and the slave motor respectively;

[0013] P1=1.5(u α1 i α1 +u β1 i β1 )

[0014] P2=1.5(u α2 i α2 +u β2 i β2 )

[0015] The difference between active power P1 and P2 is passed through the PI regulator to obtain the correction value of the given electrical angular velocity from the open loop start of the motor;

[0016] The open-loop start-up given electrical angular velocity correction value of the slave motor is compared with the set open-loop start-up given electrical angular velocity Sum and get the given electrical angular velocity from the open loop start of the motor

[0017] The open-loop starting given electrical angular velocities of the master motor and the slave motor are integrated to obtain their respective rotor position angles;

[0018] The rotor position angle is input into the 2s / 2r and 2r / 2s coordinate transformation parts in the respective motor control modules to achieve power balance control of the dual permanent magnet motors during the open-loop starting phase.

[0019] In one embodiment, during the closed-loop startup phase, the difference in q-axis current between the master and slave motors is used to compensate and correct the starting electrical angular velocity of the slave motor, so that the output electromagnetic torques of the two permanent magnet motors during the closed-loop startup phase are approximately equal, including:

[0020] The q-axis current of the main motor is given With the q-axis current given by the motor The compensation speed Δn of the motor is obtained after the difference passes through the PI regulator during the closed-loop startup phase, thereby realizing the torque balance control of the dual permanent magnet motor during the closed-loop startup phase.

[0021] In one embodiment, the method further includes dividing the operation time period of the belt conveyor, and judging the action of switching from open loop to closed loop according to the divided time periods, so as to achieve a smooth transition from open loop to closed loop switching process.

[0022] In one embodiment, the division of the operation time period of the belt conveyor includes:

[0023] During the time period from 0 to t2, the main motor starts in open loop with a given electrical angular velocity Increase linearly from 0 to the maximum value of the given electrical angular velocity at the start of the open loop The open loop starts the given electrical angular velocity maximum value Set to about 10% of the rated speed of the permanent magnet motor;

[0024] During the time period from t2 to t4, the main motor starts in open loop with a given electrical angular velocity Maintain the maximum value of the given electrical angular velocity at the open loop start

[0025] During the time period from 0 to t1, the q-axis current of the master motor and the slave motor is given Rapidly increase linearly from 0 to the given maximum value of the q-axis current The q-axis current is given by the maximum value Select the smaller value between the maximum operating current allowed by the inverter and the allowable starting current of the motor;

[0026] During the time period from t1 to t3, the q-axis current of the master motor and the slave motor is given Maintain the q-axis current at the given maximum value Remains unchanged to provide maximum starting torque;

[0027] The time period t3-t4 is the current reduction time period, and the q-axis current given value of the master motor and the slave motor is The maximum value is given by the q-axis current Start to decrease linearly.

[0028] In one embodiment, the action judgment of switching from open loop to closed loop according to the divided time periods includes:

[0029] Step 1: If the main motor satisfies the following formula, both the main motor and the slave motor switch from open-loop start to closed-loop start, otherwise proceed to step 2 for judgment;

[0030] or

[0031] Among them, θ lim Generally, it is set to about 15 degrees. lim It is usually set to about 5% of the rated current of the permanent magnet motor. The observer outputs the main motor rotor position angle, is the angle of the stator flux of the master motor relative to the a-phase axis of the slave motor;

[0032] Step 2: If the main motor satisfies the following formula, both the main motor and the slave motor switch from open-loop start to closed-loop start, otherwise proceed to step 3;

[0033] or

[0034] in, The output of the observer is the motor rotor position angle, is the angle of the stator flux of the slave motor relative to the a-phase axis of the slave motor;

[0035] Step 3: Continue to reduce the current and return to step 1.

[0036] In one embodiment, the current reduction is based on the host open-loop start electrical angular velocity reaching After a period of time, the current starts to decrease and stops decreasing when the switching condition is met.

[0037] In a second aspect, the present invention provides a device for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor, the device comprising:

[0038] The power balance control module is used to compensate and correct the starting electrical angular velocity of the slave machine by using the power difference between the master and slave machines during the open-loop startup phase, so that the output powers of the two permanent magnet motors are approximately equal during the open-loop startup phase;

[0039] The torque balance control module is used to compensate and correct the starting speed of the slave machine by using the difference in q-axis current between the master and slave machines during the closed-loop starting stage, so that the output electromagnetic torques of the two permanent magnet motors are approximately equal during the closed-loop starting stage.

[0040] In one implementation, the power balance control module includes:

[0041] Setting module, used to start the main motor open loop to a given electrical angular velocity Directly set to As the electrical angular velocity reference value of the main motor in the open-loop startup phase, The maximum value is about 10% of the rated electrical angular velocity of the permanent magnet motor;

[0042] A power calculation module is used to calculate the active powers P1 and P2 of the master motor and the slave motor respectively in a two-phase stationary αβ coordinate system;

[0043] The correction amount calculation module is used to obtain the correction amount of the given electrical angular velocity from the open-loop start of the motor by making a difference between the active powers P1 and P2 through a PI regulator;

[0044] The open-loop start-up given electrical angular velocity calculation module from the motor is used to compare the open-loop start-up given electrical angular velocity correction value from the motor with the set open-loop start-up given electrical angular velocity Sum and get the given electrical angular velocity from the open loop start of the motor

[0045] The rotor position angle calculation module is used to integrate the open-loop starting given electrical angular velocities of the master motor and the slave motor to obtain the respective rotor position angles;

[0046] The output module is used to input the rotor position angle into the 2s / 2r and 2r / 2s coordinate transformation parts in the respective motor control modules to achieve power balance control of the dual permanent magnet motors during the open-loop starting stage.

[0047] In one embodiment, the torque balance control module includes:

[0048] The compensation speed calculation module is used to set the q-axis current of the main motor With the q-axis current given by the motor The compensation speed Δn of the motor is obtained after the difference passes through the PI regulator during the closed-loop startup phase, thereby realizing the torque balance control of the dual permanent magnet motor during the closed-loop startup phase.

[0049] In one embodiment, it also includes an open-loop to closed-loop switching control module, which is used to divide the operating time period of the belt conveyor, and make an action judgment of switching from open-loop to closed-loop according to the divided time period, so as to achieve a smooth transition of the open-loop to closed-loop switching process.

[0050] The third invention, the present invention provides a belt conveyor dual permanent magnet motor control system, the system includes two motor control modules and the above-mentioned belt conveyor dual permanent magnet motor smooth and reliable starting control device, one of the two motor control modules is used for main motor control, and the other is used for slave motor control.

[0051] In one embodiment, the motor control module comprises:

[0052] 3 / 2 coordinate transformation module, used to transform the collected stator three-phase current i a1 、i b1 、i c1 , after 3 / 2 coordinate transformation, the current i in the two-phase stationary coordinate system is obtained α1 with i β1 ;

[0053] 2s / 2r coordinate transformation module, used to convert the current i α1 、i β1 and After 2s / 2r coordinate transformation, the current i in the two-phase rotating coordinate system is obtained d1 with i q1 ;

[0054] The current setting and voltage calculation module is used to set the d-axis current setting to 0 and the q-axis current setting to And respectively with the current i d1 、i q1 The d-axis voltage u is obtained by making a difference through the PI regulator d1 and q-axis voltage u q1 ;

[0055] 2r / 2s coordinate transformation module, used to convert voltage u d1 、u q1 and After 2r / 2s coordinate transformation, the voltage u in the stationary coordinate system is obtained α1 with u β1 ;

[0056] SVPWM module, used to adjust the voltage u α1 with u β1 Calculate the drive pulse signal of the inverter to drive the main motor to operate.

[0057] Beneficial effects of the present invention:

[0058] During the open-loop starting stage, the power of the two permanent magnet motors is approximately equal, and each motor outputs positive force, preventing the problem of reduced starting ability and over-voltage shutdown caused by the reaction force of one permanent magnet motor; during the closed-loop starting stage, it can effectively avoid belt damage caused by slippage between the belt and the roller, increase the service life of the belt, and design an optimization strategy for switching from open loop to closed loop during the starting stage to reduce the speed impact during the switching stage, reduce belt stress, and effectively reduce the risk of belt tearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0061] Figure 1 A flow chart of a method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor provided by an embodiment of the present invention;

[0062] Figure 2 A schematic diagram of the division of the operating time periods during the startup phase provided by an embodiment of the present invention;

[0063] Figure 3 A power balance control block diagram of an open-loop startup phase of a belt conveyor dual permanent magnet motor control system provided by an embodiment of the present invention;

[0064] Figure 4 A torque balance control block diagram of a belt conveyor dual permanent magnet motor control system in a closed-loop startup phase provided by an embodiment of the present invention;

[0065] Figure 5 The experimental effect diagram provided by the embodiment of the present invention, wherein Figure 5 (a) is a diagram showing the experimental effect without using the method of the present invention. Figure 5 (b) is a diagram showing the experimental effect of the method of the present invention.

[0066] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0067] In order to deepen the recognition and understanding of the present invention, the technical solution of the present invention is further introduced below in conjunction with the accompanying drawings and specific implementation methods. The following embodiments are explanations of the present invention and the present invention is not limited to the following embodiments.

[0068] like Figure 1As shown, the disclosed embodiment provides a method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor. The method sets one of the dual permanent magnet motors as a master motor and the other permanent magnet motor as a slave motor. The specific method steps include:

[0069] Step S100: In the open-loop startup phase, the power difference between the master and slave machines is used to compensate and correct the starting electrical angular velocity of the slave machine, so that the output powers of the two permanent magnet motors in the open-loop startup phase are approximately equal.

[0070] In order to achieve power balance between the master motor and the slave motor during the open-loop startup phase, the stator angular velocity correction link of the slave motor is introduced. The specific process is as follows:

[0071] Step S110: Start the open loop of the main motor at a given electrical angular velocity Directly set to As the electrical angular velocity reference value of the main motor in the open-loop startup phase, The maximum value is about 10% of the rated electrical angular velocity of the permanent magnet motor.

[0072] Step S120: In the two-phase stationary αβ coordinate system, the active powers P1 and P2 of the master motor and the slave motor are calculated respectively.

[0073] Furthermore, the active powers P1 and P2 are:

[0074] P1=1.5(u α1 i α1 +u β1 i β1 )

[0075] P2=1.5(u α2 i α2 +u β2 i β2 )

[0076] Step S130: The active powers P1 and P2 are differentiated and passed through a PI regulator to obtain a given electrical angular velocity correction value from the open-loop start-up of the motor.

[0077] Step S140: The open-loop start-up given electrical angular velocity correction value of the motor is compared with the set open-loop start-up given electrical angular velocity Sum and get the given electrical angular velocity from the open loop start of the motor

[0078] Step S150: The open-loop startup given electrical angular velocities of the master motor and the slave motor are integrated to obtain their respective rotor position angles.

[0079] Step S200: In the closed-loop startup phase, the starting speed of the slave is compensated and corrected by using the difference in q-axis current between the master and slave machines, so that the output electromagnetic torques of the two permanent magnet motors are approximately equal in the closed-loop startup phase.

[0080] In this embodiment, step 200 specifically includes:

[0081] The q-axis current of the main motor is given With the q-axis current given by the motor The compensation speed of the motor is obtained after the difference passes through the PI regulator during the closed-loop startup phase, thereby realizing the torque balance control of the dual permanent magnet motor during the closed-loop startup phase.

[0082] In an optional embodiment, the method further includes dividing the operation time period of the belt conveyor, and judging the action of switching from open loop to closed loop according to the divided time periods, so as to achieve a smooth transition from open loop to closed loop switching process.

[0083] Figure 2 The optimization strategy for switching from open loop to closed loop during the startup phase provided by the present invention is given, where the horizontal axis represents the startup time and the vertical axis represents the startup time. and The moment when the horizontal axis is 0 indicates the start of the belt conveyor. and The joint regulation realizes a smooth transition from open-loop to closed-loop switching.

[0084] Furthermore, the operation time period of the belt conveyor is divided into:

[0085] From 0 to t2, Increases linearly from 0 to in It is usually set to about 10% of the rated speed of the permanent magnet motor;

[0086] From t2 to t4, Maintain

[0087] Time period from 0 to t1, Rapid linear increase from 0 to in Generally, the smaller value between the maximum operating current allowed by the inverter and the allowable starting current of the motor is selected;

[0088] From t1 to t3, Maintain Remains unchanged to provide maximum starting torque;

[0089] The time period t3-t4 is the current reduction time period, and the q-axis current setting value of the main motor and 2 All from Start to decrease linearly.

[0090] During this time period, follow the steps below to determine whether the open loop switches to the closed loop:

[0091] Step 1: If the main motor satisfies the following formula, both the main motor and the slave motor switch from open-loop start to closed-loop start, otherwise go to step 2;

[0092] or

[0093] Among them, θ lim Generally, it is set to about 15 degrees. lim It is usually set to about 5% of the rated current of the permanent magnet motor. The observer outputs the main motor rotor position angle, is the angle of the stator flux of the master motor relative to the a-phase axis of the slave motor;

[0094] Step 2: If the main motor satisfies the following formula, both the main motor and the slave motor switch from open-loop start to closed-loop start, otherwise go to step 3;

[0095] or

[0096] in, The observer output is the motor rotor position angle, is the angle of the stator flux of the slave motor relative to the a-phase axis of the slave motor;

[0097] Step 3: Continue to reduce the current and return to step 1.

[0098] The following is an embodiment of a belt conveyor dual permanent magnet motor smooth and reliable starting control device of the present invention, which can be used to execute a belt conveyor dual permanent magnet motor smooth and reliable starting control method embodiment of the present invention. For details not disclosed in the embodiment of the belt conveyor dual permanent magnet motor smooth and reliable starting control device of the present invention, please refer to the embodiment of the belt conveyor dual permanent magnet motor smooth and reliable starting control method embodiment of the present invention.

[0099] In one embodiment, a belt conveyor dual permanent magnet motor stable and reliable starting control device is proposed, the device comprising:

[0100] The power balance control module is used to compensate and correct the starting electrical angular velocity of the slave machine by using the power difference between the master and slave machines during the open-loop startup phase, so that the output powers of the two permanent magnet motors are approximately equal during the open-loop startup phase;

[0101] The torque balance control module is used to compensate and correct the starting electrical angular velocity of the slave machine by using the difference in q-axis current between the master and slave machines during the closed-loop starting stage, so that the output electromagnetic torques of the two permanent magnet motors are approximately equal during the closed-loop starting stage.

[0102] Furthermore, the power balance control module includes:

[0103] Setting module, used to start the main motor open loop to a given electrical angular velocity Directly set to

[0104] A power calculation module is used to calculate the active powers P1 and P2 of the master motor and the slave motor respectively in a two-phase stationary αβ coordinate system;

[0105] The correction amount calculation module is used to obtain the correction amount of the given electrical angular velocity from the open-loop start of the motor by making a difference between the active powers P1 and P2 through a PI regulator;

[0106] The open-loop start-up given electrical angular velocity calculation module from the motor is used to compare the open-loop start-up given electrical angular velocity correction value from the motor with the set open-loop start-up given electrical angular velocity Sum and get the given electrical angular velocity from the open loop start of the motor

[0107] The rotor position angle calculation module is used to integrate the open-loop starting given electrical angular velocities of the master motor and the slave motor to obtain the respective rotor position angles;

[0108] The output module is used to input the rotor position angle into the 2s / 2r and 2r / 2s coordinate transformation parts in the respective motor control modules to achieve power balance control of the dual permanent magnet motors during the open-loop starting stage.

[0109] Furthermore, the compensation speed calculation module is used to set the q-axis current of the main motor to With the q-axis current given by the motor The compensation speed Δn of the motor is obtained after the difference passes through the PI regulator during the closed-loop startup phase, thereby realizing the torque balance control of the dual permanent magnet motor during the closed-loop startup phase.

[0110] In an optional embodiment, the device also includes an open-loop to closed-loop switching control module, which is used to divide the operating time period of the belt conveyor, and make an open-loop to closed-loop action judgment based on the divided time periods, so as to achieve a smooth transition from open-loop to closed-loop switching process.

[0111] In one embodiment, a belt conveyor dual permanent magnet motor control system is provided, which includes two motor control modules and the above-mentioned belt conveyor dual permanent magnet motor smooth and reliable starting control device, one of the two motor control modules is used for main motor control, and the other is used for slave motor control.

[0112] Further, the motor control module includes:

[0113] 3 / 2 coordinate transformation module, used to transform the collected stator three-phase current i a1 、i b1 、i c1 , after 3 / 2 coordinate transformation, the current i in the two-phase stationary coordinate system is obtained α1 with i β1 ;

[0114] 2s / 2r coordinate transformation module, used to convert the current i α1 、i β1 and After 2s / 2r coordinate transformation, the current i in the two-phase rotating coordinate system is obtained d1 with i q1 ;

[0115] The current setting and voltage calculation module is used to set the d-axis current setting to 0 and the q-axis current setting to And respectively with the current i d1 、i q1 The d-axis voltage u is obtained by making a difference through the PI regulator d1 and q-axis voltage u q1 ;

[0116] 2r / 2s coordinate transformation module, used to convert voltage u d1 、u q1 and After 2r / 2s coordinate transformation, the voltage u in the stationary coordinate system is obtained α1 with u β1 ;

[0117] SVPWM module, used to adjust the voltage u α1 with u β1 Calculate the drive pulse signal of the inverter to drive the main motor to operate.

[0118] Based on the description of the smooth and reliable starting control device for the dual permanent magnet motor of the belt conveyor, reference is made to the description of the above embodiment, which will not be repeated here.

[0119] Figure 3The invention is a block diagram of a power balance control method for a dual permanent magnet motor of a belt conveyor during an open-loop starting phase, comprising two motor control modules and a power balance control module during an open-loop starting phase, wherein one motor control module serves as a master motor control module and the other motor control module serves as a slave motor control module.

[0120] The main motor control module uses a current sensor to collect the stator three-phase current i a1 、i b1 、i c1 , after 3 / 2 coordinate transformation, the current i in the two-phase stationary coordinate system is obtained α1 with i β1 ;i α1 、i β1 and After 2s / 2r coordinate transformation, the current i in the two-phase rotating coordinate system is obtained d1 with i q1 ; Set the d-axis current reference to 0 and the q-axis current reference to And respectively with the calculated i d1 with i q1 The d-axis voltage u is obtained by making a difference through the PI regulator d1 and q-axis voltage u q1 ;u d1 、u q1 and After 2r / 2s coordinate transformation, the voltage u in the stationary coordinate system is obtained α1 with u β1 ; According to u α1 with u β1 The SVPWM module calculates the drive pulse signal of inverter 1 to drive the main motor to run.

[0121] From the motor control module, use the current sensor to collect the stator three-phase current i a2 、i b2 、i c2 , after 3 / 2 coordinate transformation, the current i in the two-phase stationary coordinate system is obtained α2 with i β2 ;i α2 、i β2 and After 2s / 2r coordinate transformation, the current i in the two-phase rotating coordinate system is obtained d2 with i q2 ; Set the d-axis current reference to 0 and the q-axis current reference to And respectively with the calculated i d2 with i q2 The d-axis voltage u is obtained by making a difference through the PI regulator d2 and q-axis voltage u q2 ;u d2、u q2 and After 2r / 2s coordinate transformation, the voltage u in the stationary coordinate system is obtained α2 with u β2 ; According to u α2 with u β2 The SVPWM module calculates the drive pulse signal of inverter 2 to drive the slave motor to run.

[0122] Power balancing module, where To set the open loop start given electrical angular velocity, To give the electrical angular velocity for the open-loop start of the main motor, To start the motor from open loop, the given electrical angular velocity is 1 / s, which is the integral module. is the angle of the stator flux of the main motor relative to the a-phase axis of the main motor, is the angle of the stator flux of the slave motor relative to the a-phase axis of the slave motor, P1 is the calculated active power of the master motor, and P2 is the calculated active power of the slave motor.

[0123] Figure 4 A torque balance control block diagram of a belt conveyor dual permanent magnet motor in the closed-loop starting phase is given, which includes two motor control modules and a power balance control module in the open-loop starting phase, one of which is used as the master motor control module and the other as the slave motor control module.

[0124] The main motor control module calculates the speed given n* and the main motor estimated speed observed by the observer The PI regulator is used to obtain the q-axis current setting value of the main motor. Use current sensor to collect stator three-phase current i a1 、i b1 、i c1 , after 3 / 2 coordinate transformation, the current i in the two-phase stationary coordinate system is obtained α1 with i β1 ;i α1 、i β1 Observed by the observer After 2s / 2r coordinate transformation, the current i in the two-phase rotating coordinate system is obtained d1 with i q1 ; Set the d-axis current reference to 0 and the q-axis current reference to And respectively with the calculated i d1 with i q1 The d-axis voltage u is obtained by making a difference through the PI regulator d1 and q-axis voltage u q1 ;u d1 、u q1 Observed by the observer After 2r / 2s coordinate transformation, the voltage u in the stationary coordinate system is obtained α1 with u β1 ; According to u α1 with u β1 The SVPWM module calculates the drive pulse signal of inverter 1 to drive the main motor to run.

[0125] From the motor control module, the motor speed setting is obtained by superimposing n* and the compensation speed Δn obtained from module three; the motor speed setting is combined with the motor estimated speed observed by the observer The q-axis current given value of the motor is obtained by differentially passing through the PI regulator Use current sensor to collect stator three-phase current i a2 、i b2 、i c2 , after 3 / 2 coordinate transformation, the current i in the two-phase stationary coordinate system is obtained α2 with i β2 ;i α2 、i β2 Observed by the observer After 2s / 2r coordinate transformation, the current i in the two-phase rotating coordinate system is obtained d2 with i q2 ; Set the d-axis current reference to 0 and the q-axis current reference to And respectively with the calculated i d2 with i q2 The difference is obtained through the PI regulator to obtain the d-axis voltage u d2 and q-axis voltage u q2 ;u d2 、u q2 Observed by the observer After 2r / 2s coordinate transformation, the voltage u in the stationary coordinate system is obtained α2 with u β2 ; According to u α2 with u β2 The SVPWM module calculates the drive pulse signal of inverter 2 to drive the slave motor to run.

[0126] Torque balancing module, i.e. the q-axis current setting of the main motor With the q-axis current given by the motor The compensation speed Δn of the motor is obtained after the difference passes through the PI regulator during the closed-loop startup phase, thereby realizing the torque balance control of the dual permanent magnet motor during the closed-loop startup phase.

[0127] The various functional modules in the embodiments of the present invention may be integrated into one processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0128] Figure 5 The figure shows the experimental effect diagram provided by the embodiment of the present invention, wherein Figure 5 (a) is the experimental effect diagram without using the balance control method. It can be seen that there is a large difference between P1 and P2 during the open-loop startup process, and P2 is less than 0 in certain periods of time. In this case, the positive force output by the main motor is in the electric state, while the reverse force output by the slave motor is in the feedback braking state, and it will cause the bus voltage of inverter 2 to increase. Figure 5 (b) is the experimental effect diagram using the balance control method. It can be seen that during the open-loop starting process, P1 and P2 are approximately equal, the main motor and the slave motor are both in the electric state, and both produce positive force, thus improving the starting ability.

[0129] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A method for controlling the stable and reliable starting of a dual permanent magnet motor of a belt conveyor, characterized in that: One of the dual permanent magnet motors is set as a master motor, and the other permanent magnet motor is set as a slave motor. The method includes: In the open-loop startup phase, the power difference between the master and slave motors is used to compensate and correct the starting electrical angular velocity of the slave motor, so that the output powers of the two permanent magnet motors are approximately equal in the open-loop startup phase; During the closed-loop startup phase, the difference in q-axis current between the master and slave motors is used to compensate and correct the starting speed of the slave motor, so that the output electromagnetic torques of the two permanent magnet motors are approximately equal during the closed-loop startup phase.

2. The method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor according to claim 1 is characterized in that: In the open-loop starting stage, the power difference between the master and slave machines is used to compensate and correct the starting electrical angular velocity of the slave machine, so that the output powers of the two permanent magnet motors in the open-loop starting stage are approximately equal, including: The open loop start of the main motor gives a given electrical angular velocity Directly set to As the electrical angular velocity reference value of the main motor in the open-loop startup phase, The maximum value is about 10% of the rated electrical angular velocity of the permanent magnet motor; In the two-phase stationary αβ coordinate system, calculate the active power P1 and P2 of the master motor and the slave motor respectively; P1=1.5(in α1 and α1 +in β1 and β1 ) P2=1.5(u α2 i α2 +u β2 i β2 ) The difference between active power P1 and P2 is passed through the PI regulator to obtain the correction value of the given electrical angular velocity from the open loop start of the motor; The open-loop start-up given electrical angular velocity correction value of the slave motor is compared with the set open-loop start-up given electrical angular velocity Sum and get the given electrical angular velocity from the open loop start of the motor The open-loop starting given electrical angular velocities of the master motor and the slave motor are integrated to obtain their respective rotor position angles; The rotor position angle is input into the 2s / 2r and 2r / 2s coordinate transformation parts in the respective motor control modules to achieve power balance control of the dual permanent magnet motors during the open-loop starting phase.

3. The method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor according to claim 1 is characterized in that: In the closed-loop startup phase, the starting speed of the slave is compensated and corrected by using the difference in q-axis current between the master and slave machines. The specific method includes: The q-axis current of the main motor is given With the q-axis current given by the motor The compensation speed Δn of the motor is obtained after the difference passes through the PI regulator during the closed-loop startup phase, thereby realizing the torque balance control of the dual permanent magnet motor during the closed-loop startup phase.

4. The method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor according to claim 1 is characterized in that: The method further includes dividing the operation time period of the belt conveyor, and judging the action of switching from open loop to closed loop according to the divided time period, so as to achieve a smooth transition from open loop to closed loop switching process.

5. The method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor according to claim 4 is characterized in that: The division of the operation time period of the belt conveyor includes: During the time period from 0 to t2, the main motor starts in open loop with a given electrical angular velocity Increase linearly from 0 to the maximum value of the given electrical angular velocity at the start of the open loop The open loop starts the given electrical angular velocity maximum value Set to about 10% of the rated speed of the permanent magnet motor; During the time period from t2 to t4, the main motor starts in open loop with a given electrical angular velocity Maintain the maximum value of the given electrical angular velocity at the open loop start During the time period from 0 to t1, the q-axis current of the master motor and the slave motor is given Rapidly increase linearly from 0 to the given maximum value of the q-axis current The q-axis current is given by the maximum value Select the smaller value between the maximum operating current allowed by the inverter and the allowable starting current of the motor; During the time period from t1 to t3, the q-axis current of the master motor and the slave motor is given Maintain the q-axis current at the given maximum value Remains unchanged to provide maximum starting torque; The time period t3-t4 is the current reduction time period, and the q-axis current given value of the master motor and the slave motor is The maximum value is given by the q-axis current Start to decrease linearly.

6. The method for controlling the stable and reliable starting of a dual permanent magnet motor of a belt conveyor according to claim 5 is characterized in that: The action judgment of switching from open loop to closed loop according to the divided time periods includes: Step 1: If the main motor satisfies the following formula, both the main motor and the slave motor switch from open-loop start to closed-loop start, otherwise proceed to step 2 for judgment; Among them, θ lim Generally, it is set to about 15 degrees. lim It is usually set to about 5% of the rated current of the permanent magnet motor. The observer outputs the main motor rotor position angle, is the angle of the stator flux of the master motor relative to the a-phase axis of the slave motor; Step 2: If the main motor satisfies the following formula, both the main motor and the slave motor switch from open-loop start to closed-loop start, otherwise proceed to step 3; or in, The output of the observer is the motor rotor position angle, is the angle of the stator flux of the slave motor relative to the a-phase axis of the slave motor; Step 3: Continue to reduce the current and return to step 1.

7. The method for controlling the smooth and reliable starting of a dual permanent magnet motor of a belt conveyor according to claim 6 is characterized in that: The basis for reducing the current is that the host open-loop start electrical angular velocity reaches After a period of time, the current starts to decrease and stops decreasing when the switching condition is met.

8. A belt conveyor dual permanent magnet motor stable and reliable starting control device, characterized in that: The device comprises: The power balance control module is used to compensate and correct the starting electrical angular velocity of the slave machine by using the power difference between the master and slave machines during the open-loop startup phase, so that the output powers of the two permanent magnet motors during the open-loop startup phase are approximately equal; The torque balance control module is used to compensate and correct the starting speed of the slave machine by using the difference in q-axis current between the master and slave machines during the closed-loop starting stage, so that the output electromagnetic torques of the two permanent magnet motors are approximately equal during the closed-loop starting stage.

9. The belt conveyor dual permanent magnet motor stable and reliable starting control device according to claim 8 is characterized in that: The power balance control module comprises: Setting module, used to start the main motor open loop to a given electrical angular velocity Directly set to As the electrical angular velocity reference value of the main motor in the open-loop startup phase, The maximum value is about 10% of the rated electrical angular velocity of the permanent magnet motor; A power calculation module is used to calculate the active powers P1 and P2 of the master motor and the slave motor respectively in a two-phase stationary αβ coordinate system; The correction amount calculation module is used to obtain the correction amount of the given electrical angular velocity from the open-loop start of the motor by making a difference between the active powers P1 and P2 through a PI regulator; The open-loop start-up given electrical angular velocity calculation module from the motor is used to compare the open-loop start-up given electrical angular velocity correction value of the motor with the set open-loop start-up given electrical angular velocity Sum and get the given electrical angular velocity from the open loop start of the motor The rotor position angle calculation module is used to integrate the open-loop starting given electrical angular velocities of the master motor and the slave motor to obtain the respective rotor position angles; The output module is used to input the rotor position angle into the 2s / 2r and 2r / 2s coordinate transformation parts in the respective motor control modules to achieve power balance control of the dual permanent magnet motors during the open-loop starting phase.

10. The belt conveyor dual permanent magnet motor stable and reliable starting control device according to claim 8, characterized in that: The torque balance control module includes: The compensation speed calculation module is used to set the q-axis current of the main motor With the q-axis current given by the motor The compensation speed Δn of the motor is obtained after the difference passes through the PI regulator during the closed-loop startup phase, thereby realizing the torque balance control of the dual permanent magnet motor during the closed-loop startup phase.

11. The belt conveyor dual permanent magnet motor stable and reliable starting control device according to claim 8, characterized in that: It also includes an open-loop to closed-loop switching control module, which is used to divide the operating time period of the belt conveyor and make an action judgment of switching from open-loop to closed-loop according to the divided time period, so as to achieve a smooth transition of the open-loop to closed-loop switching process.

12. A belt conveyor dual permanent magnet motor control system, characterized in that: The system comprises two motor control modules and a belt conveyor dual permanent magnet motor smooth and reliable starting control device as claimed in any one of claims 8 to 11, wherein one of the two motor control modules is used for master motor control and the other is used for slave motor control.

13. A belt conveyor dual permanent magnet motor control system according to claim 12, characterized in that: The motor control module comprises: 3 / 2 coordinate transformation module, used to transform the collected stator three-phase current i a1 、i b1 、i c1 , after 3 / 2 coordinate transformation, the current i in the two-phase stationary coordinate system is obtained α1 with i β1 ; 2s / 2r coordinate transformation module, used to convert the current i α1 、i β1 and After 2s / 2r coordinate transformation, the current i in the two-phase rotating coordinate system is obtained d1 with i q1 ; The current setting and voltage calculation module is used to set the d-axis current setting to 0 and the q-axis current setting to And respectively with the current i d1 、i q1 The d-axis voltage u is obtained by making a difference through the PI regulator d1 and q-axis voltage u q1 ; 2r / 2s coordinate transformation module, used to convert voltage u d1 、u q1 and After 2r / 2s coordinate transformation, the voltage u in the stationary coordinate system is obtained α1 with u β1 ; SVPWM module, used to adjust the voltage u α1 with u β1 Calculate the drive pulse signal of the inverter to drive the main motor to operate.

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